ELECTRIC STEERING - OPERATIONAL DESCRIPTION

Functional description

The electrohydraulic power assisted steering control unit M86 controls and regulates the electrically operated steering system.

The direct power supply for the control unit arrives from the battery via the line protected by fuse F72 of the maxifuse box on the on battery B99 C at pin A of connector A of M86.

Pin B of connector A of M86 is earthed.

The ignition-operated power supply arrives via a line protected by fuse F24 of the engine compartment junction unit B1 at pin 1 of connector B of M10.

The Body Computer M1 receives a direct supply from the battery via the line protected by maxifuse B99 at pin 18 of connector F of the interface with the junction unit under the dashboard B2; the ignition-controlled supply (INT) reaches pin 9 of connector F of the interface with the junction unit B2.

Control unit M86 is connected via the CAN - pins 7-8 and 5-6 of connector B - to the other nodes and in particular Body Computer M1 and instrument panel E50, to which it sends signals for the electric power steering warning light and the CITY function activation signal.

The CITY function selection button (less effort to turn the steering wheel) is located in the control panel in the centre of the dashboard, driver''s side H90 connector A: the CITY function on signal is sent to pin 20 of connector H of M1 and from there via the CAN to control unit M86.

The autodiagnostic data can be read by connecting to connector C of the Body Computer M1 - pin 9: it receives signals from pin 4 connector B of M86 via the dedicated diagnostic line.

On right hand drive versions there is also diagnostic connector R10 separate from the Body Computer.